With the growth of optical communication systems, a need for a wide variety of devices of various forms, such as switches, couplers, filters, multiplexers, etc., has arisen. An even higher need exists for reconfigurable devices, i.e., ones that can be adjusted according to the communication system requirements by applying, for example, a control signal.
State of the art optical communication systems are based on wavelength division multiplexing (WDM) that allows for substantially higher bandwidth utilization. A significant number of information signals may be transmitted over a single optical fiber using the WDM technology.
Both wavelength filtering and routing are required to take advantage of the wavelength domain in WDM systems. That is, both wavelength filtering devices as well as routing devices need to be incorporated in an optical communication system for proper functioning. Any optical communication system that uses WDM technology also employs switches, splitters and coupling devices to add/drop channels as well as to distribute information between various channels.
Usually the above functions, including switching, coupling, filtering and routing are performed in optical communication systems by using separate components. These components have limited functionality; for example, a switching device can't perform as a wavelength router and vice versa, i.e., a switching device switches all the incoming wavelengths to a specific fiber and a wavelength router distributes incoming wavelengths between different fibers in a fixed manner.
Different devices based on various physical principles have been disclosed as wavelength dependent filters, WDMs, switches, etc. Some of them are based on interferometric phenomena that use wavefront division (see, for example, U.S. Pat. Nos. 5,930,441; 5,841,583; 5,862,279; 5,351,317; 4,950,045) and amplitude division (see U.S. Pat. Nos. 4,813,756; 4,474,424). Other devices are based on diffraction phenomena and employ diffraction gratings as key components (U.S. Pat. Nos. 5,917,625; 5,206,920).
The present invention is a non-grating diffractive device based on wavefront division. Due to its diffractive nature, the device according to the present invention provides substantially higher functionality compared to interferometric devices based on wavefront division, as well as diffractive devices employing diffractive gratings.
It would be desirable to provide an optical information processing device with an increased functionality such that the same device can accomplish several information processing tasks in an optical communication system, including switching, coupling, multiplexing and/or routing.
It would be desirable to provide an optical information processing device that can be used as a building block of an all-optical communication system.
It would also be desirable to provide an optical information processing device for an optical communication system that is reconfigurable and has high capacity.